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Effect of potassium deficiency on antioxidant status and cadmium toxicity in rice seedlings

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ABSTRACT

Background: Cadmium (Cd) is one of the most toxic heavy metals and inhibits physiological processes of plants. Potassium (K) is an essential macronutrient in plants. K deficiency and Cd stress represent two different abiotic stress conditions that occur in the field simultaneously. In this study, effects of K deficiency on antioxidant status and Cd toxicity in rice seedlings were investigated.

Results: K deficiency significantly decreased K concentration in shoots and roots. However, fresh weight and dry weight of rice seedlings were not affected by K deficiency. The activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, glutathione reductase, and catalase) in K-deficient leaves were higher than respective control leaves. However, K deficiency had no effect on the content of antioxidants (ascorbate and glutathione). Cd toxicity was judged by the decrease in biomass production, chlorosis, and induction of oxidative stress. Based on these criteria, we demonstrated that K deficiency protected rice seedling from Cd stress. Moreover, chlorophyll concentration was higher in K-deficient shoots and roots than their respective control shoots and roots.

Conclusions: Our results indicated that K deficiency protects rice seedlings from Cd toxicity. This protective effect of K deficiency is mainly due to enhanced antioxidant enzyme activities but not inhibition of Cd uptake.

Electronic supplementary material: The online version of this article (doi:10.1186/1999-3110-54-2) contains supplementary material, which is available to authorized users.

No MeSH data available.


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Effect of CdCl2on the concentrations of Cd in shoots (A) and roots (B) of rice seedlings grown under K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. Control and − K seedlings were then transferred to the control and − K nutrient solution with or without 5 μM CdCl2 for 6 days, respectively. The shoots and roots were then used to determine Cd concentration. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.
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Fig8: Effect of CdCl2on the concentrations of Cd in shoots (A) and roots (B) of rice seedlings grown under K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. Control and − K seedlings were then transferred to the control and − K nutrient solution with or without 5 μM CdCl2 for 6 days, respectively. The shoots and roots were then used to determine Cd concentration. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.

Mentions: To test if K deficiency would affect the uptake of Cd, 12-day-old control and K-deficient seedlings were transferred to K-sufficient and -deficient nutrient solutions with or without 5 μM CdCl2 for 6 days, respectively. Contrary to our expectation, It was observed that shoots and roots of K-deficient seedlings had higher Cd concentration than those of K-sufficient seedlings (Figure 8A, B). Irrespective of the K supply, Cd concentration in roots (Figure 8B) was significantly higher than that in shoots (Figure 8A).Figure 8


Effect of potassium deficiency on antioxidant status and cadmium toxicity in rice seedlings
Effect of CdCl2on the concentrations of Cd in shoots (A) and roots (B) of rice seedlings grown under K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. Control and − K seedlings were then transferred to the control and − K nutrient solution with or without 5 μM CdCl2 for 6 days, respectively. The shoots and roots were then used to determine Cd concentration. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5383923&req=5

Fig8: Effect of CdCl2on the concentrations of Cd in shoots (A) and roots (B) of rice seedlings grown under K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. Control and − K seedlings were then transferred to the control and − K nutrient solution with or without 5 μM CdCl2 for 6 days, respectively. The shoots and roots were then used to determine Cd concentration. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.
Mentions: To test if K deficiency would affect the uptake of Cd, 12-day-old control and K-deficient seedlings were transferred to K-sufficient and -deficient nutrient solutions with or without 5 μM CdCl2 for 6 days, respectively. Contrary to our expectation, It was observed that shoots and roots of K-deficient seedlings had higher Cd concentration than those of K-sufficient seedlings (Figure 8A, B). Irrespective of the K supply, Cd concentration in roots (Figure 8B) was significantly higher than that in shoots (Figure 8A).Figure 8

View Article: PubMed Central

ABSTRACT

Background: Cadmium (Cd) is one of the most toxic heavy metals and inhibits physiological processes of plants. Potassium (K) is an essential macronutrient in plants. K deficiency and Cd stress represent two different abiotic stress conditions that occur in the field simultaneously. In this study, effects of K deficiency on antioxidant status and Cd toxicity in rice seedlings were investigated.

Results: K deficiency significantly decreased K concentration in shoots and roots. However, fresh weight and dry weight of rice seedlings were not affected by K deficiency. The activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, glutathione reductase, and catalase) in K-deficient leaves were higher than respective control leaves. However, K deficiency had no effect on the content of antioxidants (ascorbate and glutathione). Cd toxicity was judged by the decrease in biomass production, chlorosis, and induction of oxidative stress. Based on these criteria, we demonstrated that K deficiency protected rice seedling from Cd stress. Moreover, chlorophyll concentration was higher in K-deficient shoots and roots than their respective control shoots and roots.

Conclusions: Our results indicated that K deficiency protects rice seedlings from Cd toxicity. This protective effect of K deficiency is mainly due to enhanced antioxidant enzyme activities but not inhibition of Cd uptake.

Electronic supplementary material: The online version of this article (doi:10.1186/1999-3110-54-2) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus